Field of the Invention
The present invention relates to a composition for pattern formation, and a pattern-forming method.
Discussion of the Background
In these days, miniaturization of various types of electronic device structures such as semiconductor devices and liquid crystal devices has been accompanied by demands for miniaturization of patterns in lithography processes. Specifically, although fine patterns having a line width of about 50 nm can be formed using, for example, an ArF excimer laser beam, further finer pattern formation has been required.
To meet the demands described above, some pattern-forming methods which utilize a phase separation structure through the directed self-assembly, as generally referred to, that spontaneously forms an ordered pattern have been proposed. For example, an ultrafine pattern-forming method by directed self-assembly has been known in which a block copolymer obtained by copolymerizing a monomer compound having one property with a monomer compound having a property that is distinct from the one property is involved (see Japanese Unexamined Patent Application, Publication No. 2008-149447, Japanese Unexamined Patent Application (Translation of PCT Application), Publication No. 2002-519728 and Japanese Unexamined Patent Application, Publication No. 2003-218383). According to this method, annealing of a film formed from a composition containing the block copolymer results in a tendency of clustering of polymer structures having the same property, and thus a pattern can be formed in a self-aligning manner.
However, patterns obtained by the abovementioned method are not deemed to be yet sufficiently fine, and therefore the structure and the like of the block copolymer have been variously investigated. In connection with a technology proposed to meet the demands, a copolymer has been known in which a silicon atom is introduced into a part of a plurality of blocks of the block copolymer (see Japanese Unexamined Patent Application (Translation of PCT Application), Publication No. 2013-528664, Japanese Unexamined Patent Application, Publication No. 2013-166932 and ACS Macro Lett., 1, 1279 (2012)).